Don't imagine that you'll discover {the truth} by accumulating more knowledge. Knowledge creates doubt, and doubt makes you ravenous for more knowledge. You can't get full eating this way.
If a parricide is more wicked than anyone who commits homicide-because he kills not merely a man but a near relative-without doubt worse still is he who kills himself, because there is none nearer to a man than himself.
If a person offends you, and you are in doubt as to whether it was intentional or not, do not resort to extreme measures; simply watch your chance, and hit him with a brick.
The probability that we face global warming caused by fossil fuels is now so overwhelming that it is legitimate to doubt the motives of those who deny it
Satisfy yourself beyond all doubt that you are qualified for the course to which you now aspire.....and try to achieve something in your own land before you venture on a strange one.
No! I am not Prince Hamlet, nor was meant to be; Am an attendant lord, one that will do To swell a progress, start a scene or two, Advise the prince; no doubt, an easy tool, Deferential, glad to be of use, Politic, cautious, and meticulous; Full of high sentence, but a bit obtuse; At times, indeed, almost ridiculous— Almost, at times, the Fool.
A man was meant to be doubtful about himself, but undoubting about the truth; this has been reversed. Nowadays the part of a man that a man does assert is exactly the part he ought not to assert - himself. The part he doubts is exactly the part he ought not to doubt - the Divine Reason.